1. Technical Field
The present invention relates to a servo position adjustment method and a servo position adjustment device used for recording optical information to a recordable information recording medium.
2. Background Art
With optical disc devices that record digital information to an optical disc by irradiation with a laser beam, there may be differences between individual devices or recording media, and these can lower the quality of recording and reproduction signals.
To prevent signal quality from being diminished by these individual differences, servo position adjustment is performed during the installation of the recording medium, and the system searches for the servo position that is ideal for the specific optical disc device or recording medium.
FIG. 7 shows the structure of an optical disc in an example of prior art. In FIG. 7, 701 is an optical disc, 702 is a track, and 703 is a convex/concave pit.
As shown in FIG. 7, the optical disc 701 has a plurality of groove-shaped tracks 702 formed in a spiral shape, and the tracks 702 are irradiated with an optical beam to record marks and user data in the spaces between the marks.
Disc information, such as the recording capacity of the optical disc or the irradiation power during recording, is recorded in the convex/concave pits 703. In the past, in the recording of user data, first the convex/concave pit region would be reproduced and the servo position adjusted. For example, in the adjustment of focal position, every time the focal position is changed, a convex/concave pit string 703 is reproduced to acquire a jitter value, and the focal position that gives the lowest jitter value is selected. In the adjustment of the lens tilt position, every time the lens tilt position is changed, the convex/concave pit string 703 is reproduced to acquire a jitter value, and the lens tilt position that gives the lowest jitter value is selected. The above servo position adjustment is the same in the case of a reproduction-only disc whose entire surface is covered by convex/concave pits.
Patent Document 1: Japanese Laid-Open Patent Application H8-45081